The Kali Beejakshari Mantra is

“KRING KRING KRING HING HRING DAKSHINE KALIKE
KRING KRING KRING HRING HRING HUNG HUNG SWAHA”

Other Mantras of this goddess are

“Om aim hrim klim camundayai vicche svaha”

“Atha Kalimantraye Sadyovaksiddhiprapyivan
Aravitairyah Sarvestam Prapnuvanti Jana Bhuvih”

“Savaruhaammahabhimaghoradanshtram Hasanmukhim
Chaturbhujamkhadagmundavarabhayakaram Shivam
Mundamaladharamdevi Lolajihvandigambaram
Evam Sanchintayetkalim Shamasanalayavsinim”

Om aim hrim klim camundayai vicche svaha

This is the most used mantra of the goddess in which Om represents the sound corresponding to the absolute reality in its entirety. Aim is the syllable of knowledge (Saraswati). Hrim is the syllable of purification (Parvathy). Klim is a syllable corresponding to transformation (Kali). Camundayai is another name of Kali. Vicche means cut (cutting ones ego) and svaha is the ending of the mantra.